Over-valuation of drug-associated stimuli is a central psychological component of substance abuse. Changing these valuation patterns is key for cognitive-behavioral interventions targeted at treating drug abuse. Yet, such interventions focused on stimulus-devaluation have shown limited success, perhaps because no clear-cut mechanism has been established that reliably leads to stimulus devaluation. Our preliminary data show that stopping motor actions towards rewarding stimuli leads to a reduction in stimulus valuation. Here we will investigate the mechanisms underlying this compelling effect and we will also examine if stopping-related devaluation decreases nicotine urges in smokers. To investigate the underlying mechanisms we will perform behavioral experiments with control conditions to examine if the effect is due to stopping per se, or to other factors such as distraction and effort. We hypothesize that the devaluation effects are specific to stopping action, so no devaluation should be found in the control experiments. We further suppose that the way in which stopping action affects devaluation is by means of stopping-induced global suppression. We will index global suppression by using transcranial magnetic stimulation to measure the suppression of task-irrelevant motor effectors when participants stop their action. We hypothesize that the amount of global suppression that occurs when people stop will correspond with the amount of stimulus devaluation that occurs. Finally, we will run a behavioral experiment to determine if this stopping paradigm can be leveraged to try to reduce smoking urges in heavy smokers. Overall, this project could help to determine the exact psychological mechanism underlying stopping-induced devaluation and it could provide proof-of-concept data in smokers of the efficacy of this behavioral intervention.